Strand monitor

ABSTRACT

A monitor for spaced parallel strands which are conveyed in a direction perpendicular to the longitudinal axes of the strands. The monitor includes a stationary switch which has a switch arm to which is attached a shoe which spans at least two adjacent strands and bears against said strands as they pass by the shoe in which case the switch arm will be in a detecting position and will move to an indicating position when a broken or slack strand passes by said shoe.

United States Patent 1 Paul [ 1 Mar. 27, 1973 [54] STRAND MONITOR [75] Inventor; Frederick W. Paul, Holden, Mass.

[73] Assignee: Crompton & Knowles Corporation,

Worcester, Mass.

[22] Filed: Aug. 25, 1971 [21] Appl. No; 174,759

[52] 11.8. CI. .....340/259, 66/163 [51] Int. Cl. ...D03d 51/30 [58] Field of Search ..340/259; 66/163, 161, 158,

[56] References Cited 5 UNITED STATES PATENTS 2,436,438 2/1948 Kyneru ..66/163 2,514,719 7/1950 Quick et a]. ..66/163 Primary Examiner-John W. Caldwell Assistant Examiner-Glen R. Swann, lll Att0rney-Howard G Garner, Jr.

[57] ABSTRACT A monitor for spaced parallel strands which are conveyed in a direction perpendicular to the longitudinal axes of the strands. The monitor includes a stationary switch which has a switch arm to which is attached a shoe which spans at least two adjacent strands and bears against said strands as they pass by the shoe in which case the switch arm will be in a detecting position and will move to an indicating position when a broken or slack strand passes by said shoe.

5 Claims, 6 Drawing Figures Patented March 27, 1973 FIG! 28 26 26 FIG. 3

F l 4 Lg 5o 33 W 8% Z53 4 62 I 56%. J 49 58/ 0 G @64 I m I 5XJ MAIN I CONTROL 7O 45 CIRCUIT MAIN POWER SOURCE STRAND'MONITOR BACKGROUND OF THE INVENTION This invention relates generally to strand conveying means and particularly to strand monitoring means for apparatus in which spaced parallel strand lengths of material are conveyed in a direction generally perpendicular to the longitudinal axes of the strands.

In the textile industry there are many types of strand monitors which utilize electro-mechanical devices for indicating broken or slack strands. In all cases, the

strands are drawn from a spool or beam and conveyed along their length. The typical monitor includes a member such as a switch arm supported by a strand so that when the strand breaks, a switch is actuated or a contact is made to initiate some action which may either be a signal or a stopping of machinery so that the strand break may be repaired. In all of these cases, each strand is continuous and is advanced relative to the monitor member which is supported thereby.

In certain areas of textiles, strands are conveyed in spaced parallel lengths to fabric producing machinery such as that shown in U.S. Pat. No. 3,564,872. As shown in this patent, each strand length is advanced in a perpendicular direction to the longitudinal axis of the strand so that none of the prior art detectors could be used to indicate a broken or slack strand.

SUMMARY OF THE INVENTION A principal object of the invention is the provision of means which will detect a slack or broken strand for parallel strand conveying means described above and particular for the type of apparatus shown in the above identified US. patent.

The monitor of the present invention includes a stationary switch having a switch arm and a shoe which is attached to the end of the switch arm, and bears against the strands as they are advanced relative to the shoe. As long as the strands are evenly spaced and intact, the switch arm will be maintained in a detecting position. When a strand becomes slack or breaks, the shoe will not be restrained and the switch arm will be moved to an indicating position to initiate stopping of the strand conveying apparatus and to operate a signaling device if desired.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a first embodiment of the the invention as applied to strand conveying apparatus;

FIG. 2 is a sectional view taken along line 2-2 in FIG. 1 and showing the switch arm in detecting position', 7

FIG. 3 is a view similar to FIG. 2, showing the switch arm in indicating position;

FIG. 4 is an electrical diagram indicating the manner in which the invention is utilized to indicate a broken or slack strand;

FIG. 5 is a view similar to FIG. 2, illustrating a second embodiment of the invention and showing the switch arm in detecting position; and

FIG. 6 is a view similar to FIG. 5 and showing the switch arm of the second embodiment in indicating position.

DETAILED DESCRIPTION Referring particularly to FIG. 1, the strand monitor representing the first embodiment of the present invention is generally indicated at 10 and is shown applied to strand conveying apparatus generally indicated at 12.

Strand conveying apparatus 12 includes a pair of spaced conveyors 14 and 16, each with a plurality of spaced hooks indicated at 18. The conveyors are trained around pulleys l5 and 17 which are driven by a motor 19. Strand material is deposited from a set of hooks on one conveyor to a corresponding set of hooks on the other conveyor by means not shown so that the strand material is advanced as a plurality of evenly spaced parallel strand lengths indicated at 20 in the direction of arrows 22 toward fabric producing means generally indicated at 24. The fabric forming means could be in the form of knitting machine as shown in the above identified US. patent.

Strand monitor 10 comprises a switch unit adjacent each conveyor. Both units are identical and each includes a switch 26 mounted on a stationary bracket 28.

Switch 26 has a switch arm 30 which is pivotally attached to a shoe 32. As shown in FIGS. 2 and 3, shoe 32 is long enough in the direction of strand conveyance to span three adjacent strands provided that the center of gravity of shoe 32 is spaced from its leading end at pivot 35 a distance at least equal to the distance between adjacent strands 20 so that switch arm 30 is maintained in its detecting position. If a strand becomes slack or breaks as indicated by the dotted circle 34 in FIG. 3, shoe 32 will be supported by only one .strand indicated at 33 and will pivot about this strand so that the pivotal connection of shoe 32 to arm 30, indicated at 35, will drop below the level of the strands. When the shoe 32 is in this lower position as shown in FIG. 3, switch arm 30 is in its indicating position.

As shown in FIG. 1, two switch units are used to insure indication of a broken strand in the event that a strand, although broken, may be tangled with another strand and extends from one of the hooks with enough rigidity to support the shoe. The switches of both units are arranged in series as shown in the electrical diagram of FIG. 4 so that either switch will detect a broken strand. As shown in FIG. 1, there is a switch unit near each hook to insure that the strand being detected extends from both hooks.

Referring particularly to FIG. 4, the circuitry is divided into a high voltage section generally indicated at 36 and a low voltage section generally indicated at '38. The main control circuitry, indicated at 40, is connected to power lines 42 and 44 by a line 45 and controls motor 19 for driving conveyors 14 and 16. Circuit 40 may control other drives for the apparatus if desired. The low voltage section 38 includes a pair of low-voltage power lines 46 and 48 connected to a low voltage power source 50. A relay 52 is connected to power line 48 by a line 54 and is energized when a push button switch 56 is closed to connect relay 52 to power line 46 via line 58. A line 60 contains a normally open contact 62 and both switches 26 which are held closed when shoes 32 are in the non-detecting position shown in FIG. 2. Contact 62 is controlled by relay 52 and is closed when relay 52 is energized. An indicator light 64 is connected to power lines 46 and 48 by a line 66. A normally closed contact 68 and a normally open contact 70 are located on lines 66 and 45 respectively. Both of the contacts are controlled by relay 52.

To begin an operation, switches 26 must be closed. Push button switch S6 is depressed which energizes relay 52 and is kept energized through closure of its contact 62. Energization of relay 52 opens contact 68 to shut off light 64 and closes contact 70 to connect circuit 40 to power line 42. Push button switch 56 is the self return type which automatically opens once the operator releases the button; however, relay 52 will remain energized through its holding contact 62 and switches 26.

During the course of operation, if a strand breaks or becomes so slack that at least one of the shoes 32 swings to the position shown in FIG. 3, its corresponding switch 26 will open and relay 52 will be deenergized. Contact 62 will be opened to keep relay 52 deenergized and contact 68 will close to connect line 66 to power line 46 and energize light 64. If desired, a buzzer 65 may also be located on line 66. Contact 70 will be opened to cut off power to circuit 40 and stop the conveyors.

The switch arm is pivoted to the end of the shoe which faces the advancing strands. One reason for doing this is that the pivot point 35 will drop a maximum amount as shoe 32 rocks around strand 33. A second reason for pivoting the switch arm at this end of the shoe is that as the point 35 drops, the succeeding strand, indicated at 67, will strike the switch arm and cam it upwardly and the strands will pass harmlessly underneath. If the switch arm were pivoted at a point between its ends, it would be possible for a few strands to get caught on the shoe before the conveyors came to a stop. Although switch arm 30 is lifted back to its detecting position by the strands, the conveyors will still come to a stop since all that is required for stopping is deenergization of relay 52. Once this relay is deenergized and its holding contact is opened it will stay deenergized. Once the strand condition which initiated stopping has been corrected, switch 56 is closed to again start the conveyors.

ln FIGS. 1-3, the switch units are shown above the strands so that the shoes are supported thereby and will drop by gravity. It is contemplated that the switch could be located below the strands and the switch arm urged against the strands by a spring.

A second embodiment of the present invention is illustrated in FIGS. and 6. The switch unit of the second embodiment is indicated generally at 76 and includes a switch 26' with a pivoted switch arm 30'. This unit is similar to the one shown in the first embodiment except that the switch arm 30' is fixed to a shoe 32'. In this embodiment, shoe 32 is long enough in the direction of strand conveyance to span two adjacent strand lengths but not long enough to span three. In FIG. 5,shoe 32 is shown supported by two strands but since it is not pivoted to switch arm 30 it will also be supported by one strand, a condition which occurs periodically as the strands advance in the direction of arrow 78 relative to the shoe. When a broken or slack strand approaches the position where it would have supported the shoe by itself, the shoe will drop as shown in FIG. 6 and thereby cause switch arm 30' to move to its indicating position. The position which the broken strand would have normally occupied is indicated by a dotted circle at 80. As in the first embodiment, there may be a pair of switches 26 which would be arranged in the circuit shown in FIG. 4 and operate in the same manner as switches 26 to stop the conveyors.

Having particularly described the invention, what is now claimed is:

1. In apparatus for conveying strand lengths having means for conveying a plurality of evenly spaced parallel strand lengths in a direction which is generally perpendicular to the longitudinal axes of said strand lengths, strand monitor comprising:

a. a stationary switch including a pivoted switch arm having a detecting position and an indicating position;

. a shoe attached to end of said switch arm and having a length at least greater than the distance between two adjacent strand lengths, said shoe being arranged so as to bear against said conveyed strand lengths for maintaining said switch arm in said detecting position and allowing said switch arm to move to said indicating position when said shoe is unrestrained due to a slack or broken strand length; and

. electrical control means connected to said switch for stopping said apparatus when said switch arm is moved to said indicating position.

2. The apparatus as set forth in claim 1 wherein said shoe is fixed to the free end of said switch arm, the length of said shoe being less than twice the distance between two adjacent strands in the direction of conveyance of said strands.

'3. The apparatus as set forth in claim 1 wherein said shoe is pivotally attached to the free end of said switch arm, the length of said shoe being greater than twice the distance between two adjacent strands with its center of gravity being spaced from its leading end a distance greater than the distance between two adjacent strands and less than two times said distance between said adjacent strands.

4. The apparatus as set forth in claim 1 wherein there is a pair of said stationary switches for detecting opposite ends of a given strands as they pass by said point and connected in series with respect to said electrical control means so that either switch will be effective to stop said apparatus.

5. The apparatus as set forth in claim 1 wherein said electrical control means comprises means for producing a signal when said switch arm is in its indicating position. 

1. In apparatus for conveying strand lengths having means for conveying a plurality of evenly spaced parallel strand lengths in a direction which is generally perpendicular to the longitudinal axes of said strand lengths, strand monitor comprising: a. a stationary switch including a pivoted switch arm having a detecting position and an indicating position; b. a shoe attached to end of said switch arm and having a length at least greater than the distance between two adjacent strand lengths, said shoe being arranged so as to bear against said conveyed strand lengths for maintaining said switch arm in said detecting position and allowing said switch arm to move to said indicating position when said shoe is unrestrained due to a slack or broken strand length; and c. electrical control means connected to said switch for stopping said apparatus when said switch arm is moved to said indicating position.
 2. The apparatus as set forth in Claim 1 wherein said shoe is fixed to the free end of said switch arm, the length of said shoe being less than twice the distance between two adjacent strands in the direction of conveyance of said strands.
 3. The apparatus as set forth in claim 1 wherein said shoe is pivotally attached to the free end of said switch arm, the length of said shoe being greater than twice the distance between two adjacent strands with its center of gravity being spaced from its leading end a distance greater than the distance between two adjacent strands and less than two times said distance between said adjacent strands.
 4. The apparatus as set forth in claim 1 wherein there is a pair of said stationary switches for detecting opposite ends of a given strands as they pass by said point and connected in series with respect to said electrical control means so that either switch will be effective to stop said apparatus.
 5. The apparatus as set forth in claim 1 wherein said electrical control means comprises means for producing a signal when said switch arm is in its indicating position. 